Inhibitory Effects of Propargylic Alcohols on Algal Photosynthesis Reactions based on a Closed- system Technique.

Propargylic alcohols have a wide range of industrial applications including reactant/chemical intermediate, corrosion inhibitor, solvent stabilizer, soil fumigant and polymer modifier. These substances are semi-volatile aliphatic compounds. The present study evaluated the toxicity of 34 propargylic alcohols, including primary, primary homo-, secondary, and tertiary alcohols, based on their effects on algal photosynthesis reaction. Median effective concentrations (EC50) range from 0.743 to 3078 mg/L. Among all the propargylic alcohols tested, 1 -pentyn-3-ol is the most toxic compound with its EC50 equal to 0.743 mg/L, and 2-methyl-3-butyn-2-ol is the least toxic one (EC50=3078 mg/L). Compared to the base-line toxicity relationship (narcosis QSAR) derived previously, tertiary propargylic alcohols can be identified as nonpolar narcotic chemicals, while primary and secondary alcohols generally exhibit obvious excess toxicity in relation to the base-line toxicity. Finally, quantitative structure-activity relationships were established to correlate the observed toxicity with \ogKow and Elumo values, with R² varied from 0.76 to 0.965. The above toxicity data and QSARs are useful for risk assessment and protection of the aquatic environments, because such information is not available in the existing toxicological databases. [ABSTRACT FROM AUTHOR]